Specialized edge sewing and taping machines sew and secure peripheral edges of upper and lower mattress panels or a mattress cushion to the side panels thereof. During a mattress sewing operation, a sewing machine moves around a support relative to the mattress and performs a sewing operation about the periphery of the mattress. Chain-stitch sewing machines capable of sewing a Federal Stitch Type 401 are typically used for sewing mattress edges.
An operator, positioned adjacent to the sewing machine, compresses the mattress to create slack in the fabric panels or shell while continuously pulling an edge of the relative major face panel together with an edge of a side panel while also guiding the mattress into a stitch forming area of the sewing machine. In some applications, a steel wire or spring is arranged adjacent to the mattress seam. Moreover, and as the operator feeds the mattress panels into the sewing station, a narrow covering strip or tape is laid over the seam by a suitable and well known device and is sewn simultaneously with the seam. The strip or tape covers the seam and creates aesthetically acceptable upper and lower edges around the mattress periphery. It should be appreciated, the cumulative width of mattress materials fed into the sewing station of the machine can range in compressed thickness between about 0.187 inches and about 0.5 inches.
Mattress edge sewing and taping operations have generally required great manual effort due not only to the size and weight of the mattress but also to the constant compression the operator must apply to the mattress as well as the simultaneous tension the operator must apply to the panels mentioned above. This has been a special concern when sewing the four corners of the mattress which require extra handling and guidance efforts.
Especially when sewing an edge of a mattress, the reciprocal path of the sewing machine needle must be positioned as close as possible to a working edge of a throat plate on the sewing machine. A longer or a larger lateral distance between the path of the needle and the working edge of the sewing machine throat plate tends to allow materials, being advanced through the sewing station, to become removed from beneath the needle especially when a steel ring is arranged adjacent to the material edge being sewn Moreover, increasing the lateral distance between the path of the needle and the working edge of the throat plate proportionately increases problems involved with sewing a proper seam especially around the four corners of the mattress.
Any conventional chain-stitch sewing machine has sewing instrumentalities including a thread carrying needle and a thread carrying looper arranged in operable combination relative to each other. In such machines, the looper typically travels sideways or laterally across the path of the needle in a direction generally normal to the feeding direction of material. Because the path of the looper crosses the direction of material movement, sewing machines of this design only increase the distance between the path of the needle and the working edge of the throat plate.
Mattress edge sewing machines present a unique combination of characteristics which complicate the design thereof and are contrary to accepted and well known sewing standards. The needle on a standard chain-stitch sewing machine, between opposed ends of its stroke in a single vertical direction, travels about 1.5 times greater distance than does the looper between opposed ends of its travel in a generally lateral direction. The thickness of material having to be moved through a sewing station of a mattress edge sewing machine, however, requires the vertical travel of the needle to be significantly increased. Normally, the increased travel of the needle necessitates an increased lateral travel of the looper. Requiring the working edge of the throat plate to be positioned as close as possible to the reciprocal path of the needle, however, limits looper travel thus causing significant challenges in creating a proper chain stitch formation in a mattress edge sewing machine.
Primarily because of the thickness of material having to be feed through the machine, some mattress sewing machines have been known to use a needle feed machine. That is, a sewing machine wherein the sewing needle moves not only in a vertical path of travel but also moves with the material in the direction of material feed. As will be appreciated, designing a needle feed machine adds significantly to the cost of the machine manufacture and furthermore complicates the design of the sewing instrumentalities associated with such machine.
There are, however, significant material feeding problems associated with sewing a mattress edge simply because of the cumulative thickness of material to be moved through the sewing station of the machine. As will be appreciated, those sewing machines having a needle which reciprocally moves along a fixed path of travel have problems when considering the materials being fed through the machine have a cumulative width ranging between about 0.187 inches and about 0.50 inches. That is, if the material moving through the machine sewing station moves in the direction of feed with the needle in the work, significant damage can result to the needle, the needle bar, the needle bar drive mechanism and related sewing machine components.
Thus, there remains a need and desire for a mattress edge sewing machine which addresses the above-mentioned concerns and others while offering a low cost solution thereto.